Organic Matter Added to Bareroot Nursery Beds Influences Soil Properties and Morphology of Fraxinus pennsylvanica and Quercus rubra Seedlings

Bareroot hardwood seedling production involves intensive soil management. To increase soil organic matter (OM), nurseries commonly grow a cover crop for 1 year after every 1–2 year of seedling production. Raising soil OM levels can also be achieved through addition of soil amendments. We studied the influence of chicken manure (CM) and composted leaf, tree, and lawn trimmings (Cp) on soil properties and morphology of green ash (Fraxinus pennsylvanica Marsh.) and northern red oak (Quercus rubra L.) seedlings. CM was applied at 725, 1450, or 2900 kg ha⁻¹ (CM725, CM1450, and CM2900, respectively) and Cp was applied at 200 m³ ha⁻¹. Addition of CM and Cp significantly raised soil OM levels and altered soil chemical properties compared to the control (Ctrl). Root-collar diameter increased with addition of CM1450, CM2900, or Cp compared to CM725 or Ctrl plots for northern red oak, but was largest in soils amended with CM2900 for green ash. Conversely, height was greatest with addition of CM725 for northern red oak, but green ash seedlings were shorter in Ctrl plots than in all amendments except for CM725. Root volume of green ash and northern red oak seedlings was positively influenced by addition of CM or Cp. Seedling responses to nursery soil amendments vary with different forms and amounts of OM. Benefits to seedling growth through application of appropriate materials in the proper balance can improve seedling morphological quality and positively influence soil chemical properties.     

First records of soilborne Phytophthora species in Swedish oak forests

Thirty‐two oak stands in southern Sweden, 27 with predominantly declining trees and five with a higher proportion of healthy trees were investigated regarding the presence of soilborne Phytophthora species. Phytophthora quercina, an oak‐specific fine root pathogen, was isolated from rhizosphere soil samples in 10 of the 27 declining stands. Additionally, P. cactorum and P. cambivora were recovered from one stand each. No Phytophthora species were isolated from the healthy oak stands. The soil conditions at the sites from which Phytophthora spp. were recovered ranged from mesic sediments to moraines, with clayey to silty textures and with soil pH (BaCl₂) between 3.5 and 5.0. The results show that P. quercina is geographically widespread in oak stands in southern Sweden and indicate that this pathogen may be one of the factors involved in oak decline in Northern Europe as has already been shown for western, Central and parts of southern Europe.     

Calcium mineral nutrition increases the tolerance of Quercus ilex to Phytophthora root disease affecting oak rangeland ecosystems in Spain

Root rot caused by the soil-borne pathogen Phytophthora cinnamomi is leading to significant oak tree mortality in rangeland ecosystems in south western Spain. Susceptibility to P. cinnamomi infections of Q. ilex seedlings with a standard nutrition, deficient in K⁺, and deficient in Ca²⁺, was tested. Oaks deficient in K⁺ showed high values in Ca²⁺ content and were tolerant to the disease. Nutritional deficiency in Ca²⁺, however, did not lead to a higher K⁺ level in plants and induced poorer root development. In addition, K⁺ plant content does not appear to have any effect on pathogen tolerance. Based on these results, we conclude that satisfactory calcium nutrition may confer Holm oaks with a greater tolerance to root disease caused by P. cinnamomi. For this reason, limestone supplements are recommended as a measure against root rot caused by P. cinnamomi in rangelands in southern Spain, as a good option for control of oak root disease.     

Tracer methods to assess nutrient uptake distribution in multistrata agroforestry systems

Separate assessment of nutrient uptake by individual plants in mixed cropping with trees is impossible without tracer techniques. The different ¹⁵N-to-¹⁴N isotope ratio of atmospheric and soil N can be used to study the contribution of biologically fixed N to the nutrition of associated trees. In most cases, the assessment of nutrient uptake distribution is an appropriate way of evaluating how to improve the transfer of biologically fixed N. Radioisotopes (e.g., ³²P), stable isotopes (e.g., ¹⁵N) and rare elements (e.g., Sr) can be used to determine relative root activity distribution by applying the tracer to different soil depths or distances from trees. A broadcast application of the tracer instead of point application makes it possibe to calculate uptake values per unit area. The direct determination of nutrient pathways with such robust experiments offers considerable advantages for improving nutrient use efficiency and complementarity in multistrata agroforestry systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of oak root pruning in forest nurseries on potential pathogen infections

Despite the general practice of root pruning, little is known about the potential impact of reducing shoot/root systems of oak seedlings in this way on their future susceptibility to pathogens, for example Cylindrocarpon spp., Fusarium spp., Ilyonectria spp., Pythium spp. Phytophthora spp. or Rhizoctonia spp. In this study, root‐pruned and non‐pruned seedlings of Quercus robur grown under controlled conditions were inoculated with aggressive and less‐aggressive pathogens. Results indicated, in contrast to our initial assumption, that pathogens significantly reduced lateral root biomass more in non‐pruned seedlings, the extent of the response depending on the pathogens species. In response to pathogen pressure, pruned seedlings tended to attain a higher dry stem mass fraction, but lower dry leaf mass fraction. Pathogens also suppressed leaf mass in total root dry mass fraction (dry leaf mass/total root dry mass ratio, in g × g^?1) more in pruned than in non‐pruned seedlings. These results suggest differences in growth between non‐pruned and pruned seedlings in response to pathogen stress. In nurseries, root pruning of oak trees may enhance the reduction in leaf mass in lateral roots mass fraction resulting from pathogen infections, which may decrease seedling quality. It is therefore important to ensure a low level of inoculum of soil‐borne pathogens to minimize the risk of seedling infection.     

Long‐term effects of liming on the fine‐root standing crop of Picea abies and Pinus sylvestris in relation to chemical changes in the soil

The long‐term effects of lime application on fine roots of Norway spruce, Picea abies (L.) Karst, and Scots pine, Pinus sylvestris (L.), have been studied in five experimental forest stands subjected to different lime applications 5 to 18 years before the present study was undertaken. The effects of liming does not seem to significantly influence fine‐root development in forest stands in the long term. The only response to liming in measured root variables was a tendency to increased specific root length (SRL = fine‐root length/fine‐root dry weight, m/g). A correlation between increased SRL, decreased root biomass and increased stem volume growth was indicated. Changes in water extractable amounts of mineral elements—P, K, Ca, Mg, Mn, S, Al and Fe‐in bulk soil and rhizosphere soil from the mineral soil layers were studied in a control area and an area treated with 3830 kg CaCO₃ ha^‐1. Few significant differences were found between treatments, and then mainly in the case of Ca.     

不同浓度氨源引起的红松苗木根际pH变化及其对Fe、Mn、Cu、Zn有效性和吸收的影响

Dark brown forest soil was collected from the upper 20 cm soil layer in Changbai Mountain Research Station of Ecosystem, Chinese Academy of Sciences. The soil was amended with two different forms of nitrogen fertilizers: NO₃ as Ca(NO₃)₂, NH₄ ⁺ as NH₄Cl at the concentrations of 50, 100, 200 and 400 mg kg⁻¹respectively. The experiment was carried out with 2-yr-oldPinus koraiensis seedlings in pot. The pH change of rhizosphere soil and the contents of available Fe, Mn, Cu, and Zn in soil and leaves were analyzed. The result indicated that the addition of NH₄-N decreased the rhizosphere pH value, while the addition of NO₃-N increased the rhizosphere pH value in contrast with the control treatment. The direction and extent of the pH change mainly depended on N source and its concentrations applied. The rhizosphere pH change had a remarkable influence on the availability of the micronutrients in the rhizosphere, and thereafter affected the nutrient uptake by the seedlings. The contents of available mineral nutrients had a negative correlation with the pH value in the rhizosphere soil. The contents of available mineral nutrients in leaves were positively correlated to the levels of the available nutrients in the rhizosphere soils. Foundation item: This paper was supported by National Natural Science Foundation of China (Grant No. 30170167). Biography: CHEN Yong-liang (1969-), male, Ph. Doctor, lecture of Northeast Forestry University, Harbin 150040, Post-doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan     

Recycled alkaline paper waste influenced growth and structure of Pinus taeda L. forest

Alkaline residues of recycled paper production (ARRP) can be an alternative for correcting soil acidity and adding bases to Pinus taeda L. systems. Our aim was to investigate the effect of increasing doses of ARRP on tree, forest floor (litter and root), and soil composition in a 3-year-old Brazilian pine forest plantation. In 2007, ARRP treatments of 0, 10, 20, 30 and 40 T ha^?1 were imposed. Tree growth and needle elemental composition were evaluated in 2008 and 2018; elemental composition of the trunk was evaluated in 2018. In 2017, accumulation and composition of litter layers were assessed: new litter, old litter, first and second sublayers of fragmented litter (Fr and Fm), and the humified layer (H); roots present in F and H layers were quantified (amount and elemental composition). In addition, soil chemical properties at different depths were evaluated in 2008, 2012, and 2017. The application of ARRP improved growth by ~?16% up to 20 T ha^?1 after 10 years. Also, ARRP increased Ca concentration in needles, trunks, roots, and all litter fractions since Ca was a major component of ARRP. There was no change in total litter accumulation with ARRP application, but an increase in the humidified fraction was observed. Root growth was enhanced by ARRP, leading to great changes in root composition in Fr and H fractions. Changes in soil pH, Ca²⁺, and Al³⁺ were observed in the 0–10 cm soil layer. Findings suggest that application of ARRP to established pine forests has the potential for improving productivity.

     

Effect of six years of nitrogen additions on soil chemistry in a subtropical <Emphasis Type="Italic">Pleioblastus amarus</Emphasis> forest,Southwest China

Soil chemistry influences plant health and carbon storage in forest ecosystems. Increasing nitrogen (N) deposition has potential effect on soil chemistry. We studied N deposition effects on soil chemistry in subtropical Pleioblastus amarus bamboo forest ecosystems. An experiment with four N treatment levels (0, 50, 150, and 300 kg N ha^?1 a^?1, applied monthly, expressed as CK, LN, MN, HN, respectively) in three replicates. After 6 years of N additions, soil base cations, acid-forming cations, exchangeable acidity (EA), organic carbon fractions and nitrogen components were measured in all four seasons. The mean soil pH values in CK, LN, MN and HN were 4.71, 4.62, 4.71, and 4.40, respectively, with a significant difference between CK and HN. Nitrogen additions significantly increased soil exchangeable Al³⁺, EA, and Al/Ca, and exchangeable Al³⁺ in HN increased by 70% compared to CK. Soil base cations (Ca²⁺, Mg²⁺, K⁺, and Na⁺) did not respond to N additions. Nitrogen treatments significantly increased soil NO₃^?–N but had little effect on soil total nitrogen, particulate organic nitrogen, or NH₄⁺–N. Nitrogen additions did not affect soil total organic carbon, extractable dissolved organic carbon, incorporated organic carbon, or particulate organic carbon. This study suggests that increasing N deposition could increase soil NO₃^?–N, reduce soil pH, and increase mobilization of Al³⁺. These changes induced by N deposition can impede root grow and function, further may influence soil carbon storage and nutrient cycles in the future.     

Effects of root damage associated with Phytophthora cinnamomi on water relations,biomass accumulation,mineral nutrition and vulnerability to water deficit of five oak and chestnut species

The effects of root damage associated with Phytophthora cinnamomi on water relations, biomass accumulation, mineral nutrition and vulnerability to water deficit were investigated in pedunculate oak (Quercus robur), red oak (Quercus rubra) and holm oak (Quercus ilex) saplings over two years. Comparison was made with sweet chestnut (Castanea sativa), a susceptible species to infection by P. cinnamomi, and with a resistant hybrid chestnut (Castanea crenata × C. sativa). Trees were inoculated in 1998 and were subjected to water shortage in 1999. All inoculated sweet chestnuts died before the application of water shortage. Hybrid chestnut, pedunculate oak and red oak displayed low root susceptibility to P. cinnamomi. In these species, water relations, aerial growth and mineral nutrition were slightly affected by inoculation. By contrast, holm oak was the most susceptible oak species to P. cinnamomi as inoculated well‐watered trees displayed the highest root loss (67%) and a 10% mortality. Root loss was associated with a decrease in predawn leaf water potential, a 61% reduction in stomatal conductance, a 55% reduction in aerial biomass, a decrease in leaf carbon isotope discrimination and reduced leaf N and P contents in comparison with controls. In hybrid chestnut and pedunculate oak, water shortage resulted in a similar decrease of predawn leaf water potential, stomatal conductance and aerial biomass in inoculated and non‐inoculated trees. In red and holm oaks, soil volumetric water content of inoculated trees subjected to water shortage remained high. The effects observed in those trees were similar to those of inoculated well‐watered trees and were probably the result of root infection only.     

Fertilizer-induced Changes in Rhizosphere Electrical Conductivity: Relation to Forest Tree Seedling Root System Growth and Function

Fertilization is standard practice in forest tree seedling nursery culture. Additionally, fertilization at outplanting has potential to facilitate nutrient uptake and reduce transplant shock. Fertilization, however, may dramatically alter rhizosphere chemical properties such as pH, ion availability, and electrical conductivity (EC). These changes may inhibit root system growth and function by reducing soil osmotic potential and creating specific ion toxicities. The risk of root damage associated with high EC levels appears to be dependent on species, age of root system, and soil moisture availability. Root inhibition in container nursery culture of conifers is likely to occur above 2.5 dS m⁻¹, though threshold EC levels for bareroot culture and field plantings are largely unavailable. Fertilization at outplanting has the added risk that drought conditions may prevent leaching of excess fertilizer salts, which can increase rhizosphere EC beyond safe levels and ultimately impair root uptake of water or nutrients. For fertilization programs to be successful, a critical threshold balance must be maintained between optimizing seedling nutrient availability in the rhizosphere, while minimizing potential for root damage. Future research is needed to identify optimal EC levels for a range of species across all stages of the reforestation process, from nursery culture through plantation establishment.     

Relative contribution of initial root and shoot morphology in predicting field performance of hardwood seedlings

Single and multiple linear regression techniques were used to explain the capacity of initial seedling root volume (Rv) and first-order lateral roots (FOLR) relative to shoot height, diameter, and fresh mass to serve as important indicators of stock quality and predictors of first- and second-year height and diameter on an afforestation site in southern Indiana, USA. This was accomplished for northern red oak (Quercus rubra L.), white oak (Quercus alba L.), and black cherry (Prunus serotina Ehrh) seedlings graded into four Rv categories at establishment. Field survival was high (85–97%) for all species. Initial diameter, height, fresh mass, and Rv provided similar predictive ability of second-year field response for absolute height (R² = 0.59–0.77) and diameter (R² = 0.50–0.73) for both oak species. Initial seedling Rv was a better predictor of field response than FOLR for both oak species, though not for cherry. Multiple-variable models accounted for a greater proportion of the total variation in seedling field height and diameter than did single-variable equations. The high R² (up to 0.95) of regression models suggests field performance of these species can be reliably predicted and confirms the importance of initial seedling morphology in dictating early plantation performance.     

Soil nutrient availability and CO2 production in agroforestry systems after the addition of Erythrina poeppigiana pruning residues and native microbial inocula

To investigate the effects of microbial inocula and Erythrina poeppigiana pruning residues on soil K, NO^3?, and NH⁴⁺ concentrations, a greenhouse trial, a field experiment in an organic farm, and three in vitro tests were conducted. Under controlled conditions, weak, temporary effects (10 %) on maize seedling growth were observed on poor soils (taken from the 10–20 cm layer) in the first 2 weeks after application. Positive effects of pruning residue applications on soil K levels (0.09 cmol kg^?1, on average) were detected in both the field and greenhouse study. However, significant effects due to the addition of microbial inocula on soil K concentrations were not detected in the field; thus, microbial applications were ineffective at enhancing nutrient availability under field conditions. In contrast, in the in vitro experiments, CO₂ production was 31 % greater than that of untreated soil on the 8th and 15th days of incubation. These results highlight the importance of adding tree pruning residues to support coffee-plant nutrition. Experimental outcome data could be valuable for further studies focused on microbial application dosage and timing.     

Influence of nursery soil amendments on water relations,root architectural development,and field performance of Douglas-fir transplants

This experiment evaluated the influence of manure, peat, and vermiculite incorporated at low and high rates (0.0118 and 0.0236 m³/m²) and under two soil moisture regimes on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling (1+0 for 1+1) xylem water potential (_xylem), whole-plant growth, root architectural development, and subsequent field performance under fertilized and non-fertilized conditions. Trends in soil moisture retention were observed (high manure > high peat > control) but there were no differences in _xylem. Root length in the wetter soil moisture experiment was initially (three months) greatest for seedlings in high vermiculite and least in high manure but there were no differences among treatments at lifting (eight months). Mean height was greatest for seedlings grown in vermiculite and peat (wetter nursery experiment) after two field seasons. Field fertilization (35 g/seedling) with controlled-release fertilizer in the planting hole stimulated height growth initially, but decreased height and diameter growth during the second growing season. Dramatic improvements associated with the use of nursery soil amendments were not realized, but the failure to identify negative effects, a potential reduction in disease incidence, and improvement of nursery soil physical and chemical properties may justify their use.     

Sowing methods and mulch affect 1+0 northern red oak seedling quality

The effects of sowing depth, seedling density and mulches on northern red oak seedling survival and growth were evaluated in Wilson State Forest Nursery in southwest Wisconsin, USA. Sowing depths between 2.2 and 6.3 cm, combined with sowing densities of 75 and 150 acorns · m^-2, made up five sowing method plots. Mulch treatments of ground corncobs aged 1 year, hardwood sawdust aged 2 years, and no mulch made up 3 subplot treatments. Treatments resulted in a range of densities from 18 to 148 seedlings · m^-2. Mulch delayed emergence and increased seedling survival. Increasing sowing depth also delayed emergence. Corncob mulch increased root collar diameter; however, hardwood sawdust, aged for 2 years, decreased both root collar diameter and the number of permanent first-order lateral roots. Increasing sowing depth decreased root dry mass but increased shoot dry mass. Increasing density from 18 to 148 seedlings · m^-2decreased root dry mass in this study.     

Effects of Ca^2＋concentrations on accumulations of mineral elements in the components of Pteroceltis tatarinowii

The bark ofPteroceltis tatarinowii is a raw material for manufacturing Xuan Paper. The effects of Ca²⁺ concentrations on the accumulation of mineral elements in the bark, leaf and root ofPteroceltis tatarinowii were studied under controlled conditions. The types of Hoagland nutrient solution with three Ca²⁺ concentrations levels (200, 400 and 600 μg·g⁻¹) and a control (without Ca²⁺ were designed to culturePteroceltis tatarinowii. After 6 months, contents of seven mineral elements including Ca, K, Mg, Mn, Zn, Cu and Na in the root, leaf and bark were analyzed. The results indicated that Ca accumulations content in the root, leaf and bark had positively relation with Ca²⁺ concentrations (200, 400, 600 μg·g⁻¹), and the order of the Ca content in the three components was root>leaf>bark. Ca content in the root treated with 600 μg·g⁻¹ Ca²⁺ concentrations was 5.5 times as high as that of the control, and about 1.4 times as high as that of the root treated in 200 and 400 μg/g Ca²⁺ concentrations respectively. On the contrary, K and Mg contents in the root, leaf and bark were negatively related to Ca²⁺ concentrations, especially in the bark, and their accumulation trend followed the order of leaf>root>bark. K content in the bark treated with 600 μg·g⁻¹ Ca²⁺ concentrations was 39.3% of that of the control, and was 79.0% and 91.8% of that of the bark treated with 200μg·g⁻¹ and 400μg·g⁻¹ Ca²⁺ concentrations respectively; Mg content in the bark treated with 600μg·g⁻¹ Ca²⁺ concentrations was 23.4% of that of the control, and was 27.1% and 35.4% of that of the bark treated with 200 and 400 μg·g⁻¹ Ca²⁺ concentrations respectively. Compared with the control, the general tendency of Mn, Zn and Cu content decreased with increasing of Ca²⁺ concentrations and their contents were in the order: root>leaf>bark. Based on the results of this study, the experiment has been useful for providing academic bases in improving the bark quality ofPteroceltis tatarinowii on non-limestone soil. Foundation item: This paper is supported by National Natural Science Foundation of China (No. 39970608). Biography: Fang Shengzun (1963), male, Professor in Stiiviculture, Nanjing Forestry University, Nanjing 210027, P.R. China. Responsible editor: Zhu Hong     

Effects of chronic nitrogen application on the growth and nutrient status of a Japanese cedar (Cryptomeria japonica) stand

To investigate the potential effects of nitrogen (N) deposition on Japanese forests, a chronic N-addition experiment that included three treatments (HNO₃, NH₄NO₃, and control) was carried out in a 20-year-old Japanese cedar (Cryptomeria japonica D. Don) stand in eastern Japan over 7 years. The amount of N applied was 168 kg N ha⁻¹ year⁻¹ on the HNO₃ plots and 336 kg N ha⁻¹ year⁻¹ on the NH₄NO₃ plots. Tree growth, current needle N concentration, and soil solution chemistry were measured. Nitrogen application decreased the pH and increased NO₃ ⁻, Ca²⁺, Mg²⁺, and Al concentrations in the soil solution. The needle N concentration increased in both of the N plots during the first 3 years. Nevertheless, the annual increments in height and in the diameter at breast height of the Japanese cedars were not affected by N application, and no visible signs of stress were detected in the crowns. Our results suggest that young Japanese cedar trees are not deleteriously affected by an excess N load.     

Growth of Nursery-grown Bamboo Inoculated with Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria in two Tropical Soil Typeswith and without Fertilizer Application

A nursery experiment was conducted to assess the effect of bioinoculants (Glomus aggregatum, Bacillus polymixa, Azospirillum brasilense) on seedling growth promotion of bamboo (Dendrocalamus strictus (Roxb.) Nees.) in two soil types (alfisol, vertisol) with or without fertilizer application. Bamboo seedlings were grown in the presence or absence of bioinoculants either individually or in all combinations for 180 days in field soil under tropical nursery conditions. Shoot, rhizome and root length, dry masses, nutrient concentrations and arbuscular mycorrhizal (AM) colonized root lengths were determined at harvest. Under the experimental condition tested combined inoculation of AM fungi, PSB and A. brasilense resulted in maximum growth response both under fertilized and unfertilized conditions in both soil types. Fertilizer application enhanced the efficiencies of N, P and K uptake, whereas reduced their usage efficiencies. Though soil type did not affect microbial inoculation response, fertilizer application significantly affected plant response to microbial inoculation.     

Seed and microsite limitation for seedling recruitment of <Emphasis Type="Italic">Quercus wutaishanica</Emphasis> on Mt. Ziwuling,Loess Plateau,China

The relative influence of seed and microsite availability in the seedling emergence and recruitment of Liaodong oak (Quercus wutaishanica), which dominates the native hardwood forest in Loess Plateau, was examined by seed sowing experiments. Experiments were performed in 216 plots (30 × 30 cm), located in three typical stands (Pinus tabulaeformis plantation, Liaodong oak forest and grassland, 72 plots per stand). A seed augmentation experiment was performed in an oak forest and a conifer plantation, and a seed introduction experiment was carried out in a grassland. Three main factors were considered: seed addition, disturbance and shrub cover. The seedling number and growth in every plot were recorded continuously over 3 years. GLM multivariate was used to analyze the relationships between seedling emergence/recruitment and the explanatory variables in every stand. The results showed that seed addition in undisturbed or disturbed plots always caused significantly increased seedling emergence and recruitment in oak and conifer forests. It demonstrated that the recruitment of Liaodong oak was limited by seed and microsite availability under closed forest, and litter is one of the factors leading to microsite limitation. However, in the grassland, no treatments improved recruitment, indicating that the grassland was not suitable for seedling recruitment because of intense light and soil drought. In the conifer forest, more recruited seedlings, and lower herbivory on seedling leaves, as well as thicker stem basal diameters, indicated that the P. tabulaeformis plantation was safer for Liaodong oak seedling establishment. Unexpectedly, shrub cover did not affect the recruitment of Liaodong oak in the three stands.